A wide variety of portable electronic devices, such as mobile telephones, smartphones, personal digital assistants (PDAs), tablet computers, laptop computers and the like, include one or more antennas. A metallic or other conductive housing is considered by some to enhance the aesthetic quality of a portable electronic device. As such, an increasing number of these portable electronic devices are constructed so as to have a metallic or other conductive housing, such as a cover or a portion of a cover, formed of metallic or other conductive materials.
Some portable electronic devices are being designed to include an increased number of antennas with the number of antennas per device anticipated to continue to increase over time as a result of the requirements or other preferences of network operators. For a portable electronic device having a conductive housing, the antennas may be generally disposed within the conductive housing, thereby reducing the radiation efficiency of the antennas. Further, antenna resonance is generally dependent upon the mechanical structure. As such, antenna resonance is vulnerable to changes in the mechanical structure and, as such, may be difficult to control from the antenna perspective which may, in turn, limit the performance of the antenna.